Selena Gomez & Justin Bieber Split? Then Gomez Seen At Airport Alone [PHOTOS]

Selena Gomez tried to keep a low profile while making her way through the LAX airport on Thursday, only days after she was rumored to have gotten in a fight with Justin Bieber during their Mexico vacation that was big enough to end their relationship.

The "Who Says" singer had her passport and cell phone in her hands while she walked through the airport in black sweatpants, a white sweater, gray boots, dark sunglasses and a gray scarf covering her mouth. See photos here.

The 20-year-old actress and singer reportedly got into a major argument with Bieber days before New Year's while they were vacationing in Mexico. They were in Puerto Vallarta to celebrate the holiday and onlookers saw them arriving together at a local airport on Saturday, Dec. 29. However, an argument resulted in them returning back to Los Angeles before New Year's Eve; New York Daily News noted that Gomez left the resort on Dec. 30, and Bieber flew out on Dec. 31.

A source said, "They keep breaking up and getting back together. It's an on-again, off-again relationship. It's probably not correct to characterize this as a final breakup."

A different source, who is "especially close" to the "Beauty and a Beat" singer, said Bieber and Gomez have not seen each other since their Mexico trip.

The pair have been on and off for close to two years. Only a few weeks earlier, they were spotted in a Salt Lake City, Utah, airport cuddling and kissing. Gomez and Bieber reportedly visited a local ski resort for some fun before the Christmas holiday and a photograph showed the former Disney star sitting on Bieber's lap in an airport terminal. An onlooker said they continuously kissed while talking to each other.

Gomez tweeted a New Year's message on Jan. 1 -  "New beginnings. Fresh start. I love you all" -and a source told HollywoodLife.com the message was for Bieber.

"[Selena] said she wants to start things new with Justin again and act like they are a new couple and leave all of the drama and bulls**t behind," the source said. "She said 2013 is their year and they need to get back to basics. She wants to hold him to it though so she's letting all of her followers know."